Table 1.

Fast and slow kinetic components ofIK(M,ng) and their comparison with the kinetics of IK(M) and IMerg1

Currentτ, contribution
FastSlow
IK(M,ng)
 Total (control)117 ± 5 msec658 ± 29 msec3434 ± 159 msec
33.1 ± 2.1% (86/101)25.7 ± 1.7% (82/101)41.2 ± 2.2% (86/101)
333 ± 126 msec2356 ± 247 msec
42.5 ± 5.1% (14/101)57.6 ± 5.1% (15/101)
 Fast (WAY-insensitive)104 ± 7 msec (37)
 Slow (WAY-sensitive)456 ± 29 msec2718 ± 156 msec
41.7 ± 3.5% (34/36)58.3 ± 3.5% (36/36)
IK(M)93 ± 5.6 msec (n = 15)
Imerg1a183 ± 10.6 msec1012 ± 85 msec
64.6 ± 2.4% (22/23)35.4 ± 2.4% (23/23)
Imerg1b37.1 ± 19.4 msec112 ± 42.5 msec
70.8 ± 15.8% (3/3)29.2 ± 15.8% (3/3)
  • IK(M,ng), IK(M),Imerg1a, and Imerg1b were recorded from NG108-15, mouse sympathetic, and CHO cells, respectively. Deactivation was recorded in response to a voltage step to −50 mV from a holding potential of −20 mV (IK(M,ng) andIK(M)) or 0 mV (Imerg1aand Imerg1b). Means ± SEM of τ and contributions were obtained from deactivation relaxations recorded at −50 mV. Number of cells in parentheses; see Results.